The machines which concern the invention are those where one or more operators manually load the corners of an article such as a sheet or table cloth onto sheet corner-receiving clipping or clamping means. Such machines are described in the following patent specifications: U.K. Nos. 1105901, 1168513 and U.S. Pat. No. 3,664,046.
Production speeds of modern laundry processing equipment (such as ironing and folding machines) have risen significantly. A single or a number of operators cannot safely load the sheet corners to match desired production requirements with the sheet clipping or clamping means heretofore developed.
According to the known state of the art described in the above mentioned patents, the loading and transfer of the sheet corners present undesirable limitations. Clamping and spreading means are arranged to move inward and outward from a fixed central feed line position. A critical mechanical movement is necessary for the clamping means to receive the top edge corners of the sheet. The loading positions where multi-operator usage can be effectively employed is limited to the practical mechanics of the positioning movements of clipping or clamping means to a central transfer position.
A further limitation is the portion of the corner which is actually gripped by the clamp. This is a relatively small area of the top edge of the sheet and consequently limits the amounts of desirable tensioning force which can be exerted to spread the leading edge of the sheet without causing damage and tearing of the fabric. Outward spreading speeds and forces must therefore be restricted to prevent such damage occurring.
An object of the present invention is to increase with safety to the operators the transfer speed of the corners of a sheet from a loading position to the clamping means.
It is of paramount importance that the operators not be exposed to accidental contact with the sheet spreader clamps when they are in motion, since they travel at a dangerously high rate of speed. It is this high rate of speed which can be achieved with such spreader clamps that necessitates multiple loading stations to provide the most rapid utilization of machine feed rate.
More specifically, the purpose of the invention is to provide improved means for initially clip loading the corners of a sheet, coupled with a fast transfer of the loaded corners from clipping means to the clamping means which effect a high speed spreading and tensioning of the leading edge portion of the sheet in preparation for an onward feeding process of the sheet.